1. Field
An aspect of the present invention relates a display device. More particularly, an aspect of the present invention relates to a display device using an ambient light sensor (ALS) driving method.
2. Description of the Related Art
As a representative display device, a liquid crystal display (LCD) includes two panels provided with pixel electrodes and a common electrode, and a liquid crystal layer having dielectric anisotropy interposed between the two panels. The pixel electrodes are arranged in a matrix format and are connected to a switch such as a thin film transistor (TFT) to sequentially receive a data voltage by row. The common electrode is formed over the entire surface of the panel to receive a common voltage. The pixel electrodes, the common electrode, and the liquid crystal layer interposed between the pixel electrodes and the common electrode form a liquid crystal capacitor from a circuital view, and the liquid crystal capacitor and a switch connected thereto become a basic unit forming a pixel.
In the liquid crystal display (LCD), an electric field is generated in the liquid crystal layer by applying voltages to the two electrodes, and transmittance of light passing through the liquid crystal layer is controlled by controlling the electric field to thereby display a desired image. In order to prevent a degradation phenomenon that occurs when the electric field is applied in the liquid crystal layer in one direction for a long time, polarities of the data voltage with respect to a common voltage are inverted for every frame, every row, or every pixel.
The ALS driving method as a driving method boosting a voltage of a pixel boosts the voltage of the pixel electrode that is floated after a gate voltage is off by coupling it with the voltage of an ALS line. The boosting of the voltage of the pixel electrode may be induced by increasing or decreasing the voltage of the boost line during one frame. The ALS driving method may reduce a source output voltage of a driving circuit, thereby reducing power consumption. Also, the ALS driving method may increase the pixel voltage, and the response speed of the liquid crystal may be improved through the application of the high pixel voltage.
However, the ALS line has a same direction of a scan line and overlaps the data line, such that the voltage of the boost line may have noise by coupling with the voltages applied to the data line and the scan line.
For example, the voltage of the boost line is generated by the coupling when the gate voltage is on. The voltage generated in the boost line must be restored until the gate voltage is off. If the voltage generated in the boost line is not restored until the gate voltage is off, the output signal of the boost line is increased. Particularly, the coupling influence of the boost line is increased further away from the output terminal of the boost signal, and the component that the voltage of the boost line is not restored is increased when the gate voltage is off.
The deviation of the component that the voltage of the boost line is not restored is increased when the gate voltage is off generates the difference between the pixel voltages, and thereby crosstalk may be generated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.